I was on another site and someone was talking about some plugs he was turning. Sounded like he was doing a good job but he mentioned something about trying to move the belly weight on his danny's a little further forward to try to imitate the static stance of a Tattoo’s danny plug in the water. Plus he was a little disappointed with the water test of his first plug. As usual I offered some unsolicited advice, cause I’m a little obnoxious like that sometimes. The worst part is I really don’t know much about making wooden plugs, but I do know a lot about hydrodynamics, statics and dynamics so I offered some advice more along the lines of practical engineering considerations.
I’m reposting some of this here so I can get some input from you guys. His problem peaked my interest a little bit and got me thinking about what makes certain plugs do certain things. I also wanted to know if what I said makes any sense in the plug making world and if it doesn’t I can go back and apologize for being a presumptuous ass!
Here’s my shpeel:
“I've never made plugs before, but I know a little about hydrodynamics. I'd make a guess that you should take the unweighted Danny's and design it so the unweighted version will balance on your finger at the widest part of the plug (design so the center of gravity is at the belly). Once you locate the CG on the plug, you should insert the weight right at this point. The idea is that it will allow the plug to move about freely and easily, centered at this point with equal mass in either direction (balance), effectively bringing down the minimum speed at which you need to move the plug to get it to wiggle. The slower a retrieve it takes to get a danny to start rolling is one of the methods I use to measure the effectiveness when tuning a particular model.
I could be wrong, but I'm sure some of the more experienced plug builders could give you some recommendations. It just seems counter-intuitive to me to bring the weight forward to help the plug roll. Also, plugs shouldn't necessarily be designed to cast well, they should be built to perform once they are in the water. Sometimes people get so fixed on getting maximum distance they forget that performance is much more important than castability (most of the time striper fishing anyway)."
At this point he mentioned that the Tattoo’s sat a little higher in the stern and he thought that meant the CG was moved forward which allowed the tail to wiggle a little more. The next bit is me thrusting my fascist, unfounded plug building wisdom on him regarding that theory:
"I don't have a tattoo's dannys but the CG location is not the only thing effecting the way it floats.
There are two major things to consider when designing a submerged body. The center of gravity (CG), or fulcrum point as you described it, and the center of buoyancy (CB). You determine the center of gravity out of the water but you typically can only determine the location of the center of buoyancy once the object is in the water.
The two have a very important relationship with one another and both should be considered when designing. The center of buoyancy is the place where if you held the plug underwater with you finger the sum of the buoyant forces acting on that plug would be located at this point. It's like the opposite of the CG test. Hold the plug underwater, with your finger on top, and where it balances is the CB. Designing the plug with these two points to be coincident with one another will give you the most freely moving version of a plug. Playing games with the separation of these two points along the length of the plug is what helps to give different designs different personalities in the water.
Sorry if that was a little confusing, but I was just trying to find a simple way to explain it. You said the tatto's floats with the tail up a little which means the CB is toward the tail but does not necessarily mean the CG has been brought forward.
Was that helpful? Again, I'm talking about submerged bodies in general and not necessarily the art of making plugs which I really know little about.”
You guys have any insight… John?...
|
|